Physicochemical and bacteriological evaluation of sachet water sold in Minna metropolis, Niger State, Nigeria

Abstract

Physical assessment of the package labels (product name, manufacturing address, National Agency for Food and Drug Administration (NAFDAC) registration number, manufacturing and expiry date and batch number on the labeling) and quality evaluation of the physicochemical and bacteriological properties of the water samples collected was assess and analyzed in relation to level of compliance with package water recommended standards. Four (4) clusters were considered in which three samples were collected from vendors in each cluster making up a total of twelve (12) samples. Physical examinations revealed 100% compliance to standards in terms of the product name, manufacturing address and NAFDAC registration number but zero percent compliance for manufacturing and expiry dates but only about 17% of the samples had a batch number on the labeling. The physiochemical parameters show appreciable compliance to standards with an ambient temperature of 28 °C, pH range of 6.5 to 8.5 and conductivity values ranged between 104.67 - 225.67 µS/cm still lower compared to the maximum range of 1000 µS/cm by Nigerian Industrial Standard (NIS). Samples turbidity results recorded zero value for SWA1, SWB2, SWC3, SWE5, SWG5, SWH6, SWI7, SWJ8 and SWK9 except for sample SWD10, SWF11, and SWL12 with a turbidity of 2.00, 2.00 and 3.00 NTU, respectively and were still within NIS/WHO limit of 5 NTU. Total dissolved solids (TDS) values ranged from 70.20 - 171.67 mg/L but still within the threshold limit of 500 mg/L recommended by NIS. The bacteriological parameters gave total bacterial count (TBC) ranged between 1 - 16.50 cfu/cm3 accounting for SWB2=2.00, SWC3=1.50, SWD4=2.00, SWE5=1.00, SWF6=5.50, SWG7=4.00, SWH8=5.00, SWI9=13.00, SWJ10=8.50, SWK11=16.50,and SWL12=16.00 cfu/cm3 above the WHO limit of zero cfu/cm3 except SWA with 0.00 cfu/cm3 in conformity with the standard limit while TCC ranged from 1-1.50 cfu/cm3 for SWC3=1.50, SWD4=1.00, SWE5=1.00, SWG7=1.00, SWH8=1.50 and SWK11=1.50 cfu/cm3 which is all above the WHO limit of 0.00 cfu/cm3except six samples (SWA1, SWB2, SWF6, SWI9, SWJ10 and SWL12) having 0.00 cfu/cm3 accounting for 50% samples compliance with the tolerance limit. The concentration of Pb, Zn, Fe, and Cr in the samples was below the WHO/SON tolerant level of 0.01 mg/L for Pb, 5 mg/L for Zn, 0.3 mg/L for Fe and 0.05 mg/L for Cr except for samples SWF6, SWG7, and SWJ10 with Pb concentration of 0.04, 0.032, and 0.050 mg/L respectively, above permissible limits of WHO/SON. The corrosion of pipes used in the water processing may account for the Pb concentration hence, regular assessment of the sachet water products should be ensured by the regulating agencies to promote both water and health safety.